The present invention relates to techniques for producing the perception of a moving viewpoint within a three-dimensional space presented on a display.
Fairchild, K. M., Poltrock, S. E., and Furnas, G. W., "SemNet: Three-Dimensional Graphic Representations of Large Knowledge Bases," in Guindon, R., ed., Cognitive Science and its Applications for Human-Computer Interaction, Lawrence Erlbaum, Hillsdale, N.J., 1988, pp. 201-233, describe SemNet, a three-dimensional graphical interface. SemNet provides semantic navigation techniques such as relative movement, absolute movement, and teleportation. Section 5 discusses navigation and browsing, including viewpoint movement techniques such as moving the viewpoint close to an element that the user needs to inspect. Section 5.2 describes methods for moving the viewpoint to determine the portion of a knowledge base that is displayed. Section 5.2.1 describes relative movement, with independent controls for three orthogonal rotations of the viewpoint and movement forward and backward along the line of sight. Tools for adjusting the velocity of movement and rotation are provided, but relative movement is slow and awkward to use. Section 5.2.2 describes absolute movement in which the user can point to a desired viewpoint location on a map of the three-dimensional knowledge space. The map can have two or three two-dimensional parts, with each part representing a coordinate plane in the space, and the user can manipulate the position of the viewpoint by moving an asterisk in one plane at a time using the mouse. A filter ensures that the viewpoint moves smoothly, retaining the experience of travel through a three-dimensional space. Although absolute movement is quicker and easier to use than relative movement, it is not very accurate and moving the viewpoint in more than one map is confusing. Section 5.2.3 describes teleportation, in which a user can pick a recently visited knowledge element from a menu and instantly move to the location of the knowledge element. Section 5.2.4 describes hyperspace movement, in which the nodes connected to a selected knowledge element are temporarily moved to positions around it, and then snap back to their original positions after a new node is selected.
Burton, R. R., Sketch: A Drawing Program for Interlisp-D, Xerox Corporation, Palo Alto Research Center. ISL-14, August 1985, pp. 44-49, describes techniques for changing the part of a sketch seen in a window. A sketch is a collection of elements such as lines and text. The sketch has a world coordinate space and the position of each element is given by values in this space. A sketch is viewed and edited inside a window, which shows a region of the coordinate space of a sketch and displays any of the elements that are in the region. The region is determined by the window's scale, its size, and the values of its left and bottom coordinate. As illustrated in FIGS. 59-62, a window's scale can be changed by the Move view command or the Autozoom command. The user can select the Move view command from the command menu and then use the cursor to specify a new portion of the sketch that is to appear in the window by depressing a mouse button at one corner and sweeping the cursor to the other corner; the specified region is scaled to fill the sketch window. The user can select the Autozoom command from the command menu, then move the cursor to the point in the sketch around which zooming will occur, then press one of two buttons to indicate whether to zoom in or zoom out; zooming in makes the image larger but with the point under the cursor in the same location, while zooming out makes the image smaller with the point under the cursor in the same location. The image continues to grow or shrink around the position of the cursor as long as either button is down.